// Map 对象保存键值对。任何值(对象或者原始值) 都可以作为⼀个键或⼀个值。
const launches = new Map();
// 数据⽰例
const launch = {
 flightNumber: 100,
 mission: 'Kepler Exploration X',
 rocket: 'Explorer IS1',
 launchDate: new Date('December 27, 2030'),
 destination: 'Kepler-442 b',
 customer: ['GKD', 'NASA'],
 upcoming: true,
 success: true,
};
// 设置键值对
launches.set(launch.flightNumber, launch);
module.exports = {
 launches,
};
